Wild horse genome reveals hidden costs of domestication
-
Corey Fedde Staff
The world鈥檚 last wild horses, the Przewalksi鈥檚 horses, might help us understand the effect domestication has on a genomic scale.
Przewalksi鈥檚聽horses, discovered in the 1870s in the Asian steppes, are the planet鈥檚 closest thing to wild horses. They faced extinction, but due to a committed conservation effort in the 1960s, more than 2,000 individuals remain. Most of them are living in reintroduction reserves.
A research team, including Ludovic Orlando of the University of Copenhagen鈥檚 Natural History Museum of Denmark, sequenced the complete genomes of eleven of the remaining wild horses and five historical, museum specimens. They compared them to the genomes of 28 domesticated horses. In this way the team is able to 鈥渁ssess the genetic impact of more than 100 years of captivity in what used to be a critically endangered animal,鈥� as Dr. Orlando told
, which are published by聽in the journal Current Biology, show that 110 years of captivity have had a negative impact on the Przewalksi horses. The horses had lower genetic diversity and increased inbreeding. They also had signs of domesticated genes, hinting that domesticated horses might have mixed with the breed.
The greatest genetic differences between domesticated and wild horses appeared to involve metabolism, cardiac disorders, behavior, reproduction, muscle contraction, and signaling pathways, according to a .
Orlando did have some good news for the horses: "Even though Przewalski's horses went through an extreme demographic collapse, the population seems to recover, and is still genetically diverse鈥� There is, thus, hope for endangered populations, fighting similar demographic issues."
This study is the latest in Orlando鈥檚 quest to map out the genetic changes of domestication. In 2014, he conducted a similar study聽investigating which genes were favored as horses turned from wild animals to humans鈥� companions.
As Arne Ludwig of the Leibniz Institute for Zoo and Wildlife Research told Reuters in response to Orlando鈥檚 last study, 鈥淐omparing ancient genomes to modern genomes is tricky.鈥�
